1. Field of the Invention
The subject invention is directed to erosion control products and is particularly directed to biodegradable erosion control blankets.
2. Description of the Prior Art
Erosion control blankets and the like are well known and are used for reducing or minimizing erosion particularly on hillsides and slopes which are barren and reseeded. The blankets reduce rainfall impact, reduce the velocity of runoff water, and shield the soil surface from the wind. The blankets enhance plant growth by moderating soil temperatures and reducing evaporative losses, keeping moisture in the soil where it is available to foster the growth of vegetative cover. Many types of erosion control blankets are currently available such as, by way of example, erosion control blanket products manufactured by North American Green of Evansville, Ind.; Erosion Control Landscape and Construction Products manufactured by American Excelsior Company, Arlington, Tex.; Erosion Control Products manufactured by Geo-Synthetics, Inc., Waukesha, Wis.
Erosion control blanket technology has been continuously advancing over the years, as shown, by way of example, in U.S. Pat. No. 3,315,408 entitled "SOLUBLE FIBROUS MATERIAL FOR CONTROLLING SOIL EROSION" issued to S. G. Fisher Apr. 25, 1967. The Fisher patent discloses a woven grid of a soluble fibrous material which may be placed on a hillside or slope to prevent erosion during the revegetation process. The fibrous material is soluble over a period of time by the natural reaction of the environment and is dissolved as the vegetation takes hold.
U.S. Pat. No. 3,805,446 entitled "MULCHING FILM" issued to K. Aoyagi on Apr. 23, 1974 shows a mulching film of synthetic material having a plurality of slits adapted to permit the plants to sprout through the film. The film is not biodegradable or soluble.
U.S. Pat. No. 3,810,328 entitled "MULCH SHEET" issued to R. C. Brian et al on May 14, 1974 shows a bonded mulch sheet containing a plastic base with a kraft cover.
U.S. Pat. No. 3,955,319 entitled "HORTICULTURAL SHEET MULCH" issued to N. J. Smith on May 11, 1976 discloses a mulch sheet having a plurality of slits for permitting the plants to sprout through the sheet. The sheet is designed to retard weed growth, is typically of a plastic material and is not biodegradable.
U.S. Pat. No. 4,353,946 entitled "EROSION CONTROL MEANS" issued to G. Bowers on Oct. 12, 1982 shows an erosion control blanket made of wood wool fibers which are biodegradable over a period of time and are dissolved into the soil.